A heat exchanger is an apparatus that transfers heat between two or more fluids. The heat exchanger may be applied to various industrial fields, such as vehicles, boilers, ships, and facilities.
Such heat exchangers include various types, such as a pin tube type heat exchanger, a shell tube type heat exchanger, and a pin type heat exchanger.
The pin tube type heat exchanger may be easily manufactured, but the durability of the pins may be lowered and heat transfer efficiency may deteriorate. The shell tube type heat exchanger has an excellent pressure-resistant property and high component reliability, but the structure of the shell tube type heat exchanger is complex and the weight thereof is heavy. The plate type heat exchanger has an excellent pressure-resistant property (of not less than 200 bars) and has high heat transfer efficiency, but the degree of freedom of installation is limited.
A heat exchanger for a vehicle, such as an EGR cooler, an exhaust boiler or an EGR gas boiler of a waste heat recovery system is a technology of recovering thermal energy as a thermal fluid such as EGR gas or exhaust gas exchanges heat with a coolant such as cooling water or working fluid, and the heat exchanger for a vehicle may have a high pressure condition of a maximum of 30 bars or a high temperature condition, and the high-temperature/high-pressure condition may influence the durability of the components.
Meanwhile, because the shell tube type heat exchanger may be widely used due to its excellent pressure-resistant property and component reliability and may secure a widely larger installation space in a plant or a ship, the shell tube type heat exchanger may be used without limitation, but as the installation space in a vehicle is relatively narrow, the degree of freedom of design, the reliability of components, and the easiness of the maintenance and repair have to be considered when the shell tube type heat exchanger is applied.
In this way, in the shell tube type heat exchanger according to the related art, because the shells have to be pressure-resistant containers having a sufficient pressure-resistant property as coolant of a high pressure (not less than 30 bars) passes through the interior space of the shells, and the outsides of the shells have to be separately insulated to prevent heat recovered from the thermal fluid from being dissipated to the outside, manufacturing costs of the shell tube type heat exchanger are high.
Further, as the thermal fluid, such as exhaust gas or EGR gas, passes through the heat exchanger tube of the conventional shell tube type heat exchanger, particulate matters (PMs) may be attached to the inner surface of the heat exchanger tube, and accordingly, the heat exchanger performance may become very low as the interior of the heat exchanger tube is blocked.
Further, according to the conventional shell tube type heat exchanger, the heat exchanger tube installed in the interiors of the shell cannot be easily separated, and accordingly, contaminants, such as the particulate matters, cannot be easily washed.